Refrigeration apparatus for air conditioned passenger vehicles



Dec. 15; 1942. R. T. PALMEVR 2,3045951 REFRIGERATION-APPARATUS FOR AIR CONDITIONED PASSENGER VEHICLES Filed Aug. 20, 1941 mutao tuh HO Patented Dec. 15, 1942 REFRIGERATION APPARATUS FOR AIR CONDITIONED PASSENGER VEHICLES Robert T. Palmer, Sharon, Mass., assignor to B. F. Sturtevant Company, Boston, Mass.

Application August 20, 1941, Serial No. 407,580

5 Claims.

This invention relates to refrigeration apparatus and relates more particularly to thermostatically controlled refrigeration apparatus for air conditioned railway passenger cars.

On some railway lines, it is preferred to use ice for the source of refrigeration. The ice is usually contained in bunkers on the under side of the cars and ice water is pumped to overhead cooling coils. Around the first of October each year it is the custom to drain the ice bins and to discontinue air conditioning, the reason being that the risk of the water freezing due to a sudden drop of temperature, is too great to justify continuation of the air conditioning even though there may be many warm days that make it desirable.

This invention provides an inexpensive addition to such a system whereby the air may be cooled without refrigeration in the border line months between summer and winter. Spray nozzles and a pump are added in the overhead cooling unit, the pump when the ice water system has been drained, recirculating water in a closed circuit including a sump and the nozzles. A wet bulb thermostat exposed to outdoor air acts when the wet bulb temperature of the outdoor .air is between say 70 F. and 50 -F., to close the usual recirculated air dampers, and to open the usual outdoor air dampers for 100% outdoor air. At the same time, the wet bulb thermostat starts the-pump for recirculating the spray water. The outdoor air is washed and is cooled by evaporative cooling and supplied into the passenger space. If the temperature within the car falls too low, an indoor thermostat first shuts down the pump and if the temperature continues to drop, the steam heat is turned on.

Not only is air cooling and cleaning provided during the Warm days but 100% outdoor with its freshness and absence of odors is employed over extended periods.

An object of the invention is to provide air cooling without the expense of refrigeration in the border line months between winter and summer.

The invention will now be described with reference to the drawing, which illustrates diagrammatically one embodiment of an air conditioning system utilizing this invention.

The overhead air cooler 5 contains the usual ice water, air cooling coils 6, and the usual steam heating coils l. The usual bin 8 on the underside of the car supplys ice water which is circulated by the pump 25 through the coils 6. The drain connection 4 is provided for draining the bin 8, the coils B and the piping connecting them, about October 1st of each year.

The usual outdoor air dampers 9 and recirculated air dampers ID adjustable by the motor II are provided and admit air to the inlet of the cooler fan I2.

This invention adds a sump l3 and spray nozzles 14 to the cooler 5, and provides in the sump the pump 15 .driven by the motor I 6. The pump 15 recirculates water ,from' the sump through the nozzles.

The Wet bulb thermostat l1 ,isexposed to ,outdoor air and its fixed contacts corresponding to a wet bulb temperature of 70 and 31 corresponding to a wet bulb temperature of 50 are connected together by the conductor 29 and are connected in series with its movable contact 32 and with the damper motor II .and the electric source H8. The movable contact is moved along and above and below the conductor 29, by the bellows 35 which is ,connected by the tube 33 to the usual wet bulb thermometer 3 4. The pump motor 16 is connected in series with the thermostat 20 and to the damper motor I I.

When the outdoor wet bulb is between '50" F. and 70 F., the thermostat closes .thecircuit and energizes the motors, causing the outdoor dampers 9 fully vtoopen, the recirculated air dampers I0 fully to close, the pump motor [6 to start the pump l5. Conditions are right at such times for evaporative cooling and 100% outdoor. air;is-evaporatively cooled and supplied into the car.

Below F., no cooling is required and above F., conditions are not favorable for evaporative cooling and so atsuch times the contact 32 of the thermostat I1 moves below the contact 31 and above the contact 30 respectively and through opening the above describedcircuitacts to stop the pump and to adjust the dampers for 25% outdoorair and recirculated air.

If during the evaporative cooling cycle the car temperature falls too low, the indoor thermostat opens the circuit of the pump motor Hi causing the pump to stop and the .evaporative cool ing to cease. If the car temperature continues to drop, the thermostat 2| whichis connected in series with the solenoid 22 controlling the valve 23 between the steamsource 24 and the steam coils l, and the electric source [8, opens this circuit to open the steamvalve 23 and to sup ply heat.

The above described auxiliary system may be used alone .for cooling during the border line months as described or may be used witn'the usual ice system during the summer months for reducing ice consumption. If used with the ice cooling system, the pump motor 26 may be connected in shunt with the pump motor It as indicated by the dotted lines of the drawing so that the indoor thermostat 20 controls the ice cooling as well as the evaporative cooling. Then when the ice bin 8 is drained, the switch 21 may be opened for disconnecting the pump motor 26.

Since the pump l5 and its associated water lines, etc. are contained within the car, the temperature of which is never permitted to drop to freezing temperatures, and since the thermostat ll switches from 100% to 25% outdoor air when the outdoor temperature approaches freezing, there is no danger of the auxiliary spray system freezing up upon a sudden drop of temperature during the border line months.

While one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement of apparatus disclosed, as modifications therefrom may be suggested by those skilled in the art without departure from the essence of the invention.

What is claimed is:

1. Air conditioning apparatus comprising a compartment containing air cooling tubes adapt ed to receiv ice water in the cooling season, said compartment having a sump in its lower portion, spray nozzles in said compartment for spraying water in the air passing therethrough, means in cluding a pump in said compartment for recirculating water from said sump through said nozzles, means forming outdoor air and recirculated inlets into said compartment, dampers in said inlets, and means including a wet bulb thermostat exposed to outdoor air for adjusting the dampers in the recirculated air inlet towards closed position and the dampers in the outdoor air inlet towards open position, and for starting said pump when the Wet bulb temperature of the outdoor is below a predetermined maximum temperature :and above a'predetermined minimum temperature.

, '2; Air conditioning apparatus comprising a ,compartment containing air cooling tubes'a-dapted to receive ice water in the cooling season, said compartment having a sump in its lower portion,

spray L nozzles in said compartment for spraying water in the air passing; therethrough, means ineluding a pump in said compartment for recirculating water from said sump through said nozzles, means forming outdoor air and recirculated inlets into said compartment, dampers in said inlets, means including a wet bulb thermostat exposed to outdoor air for adjusting the dampers in the recirculated air inlet towards closed position and the dampers in the outdoor air inlet towards open position, and for starting said pump when the wet bulb temperature of the outdoor air is below a predetermined maximum temperature and above a predetermined minimum temperature, and means including an indoor thermostat I "for deenergizing said pump when the indoor temperature is below a predetermined point.

'1' 3. Air conditioning apparatus comprising a I compartment containing air cooling tubes adapted to receive ice water in the cooling season, said compartment having a sump in its lower portion,

spray nozzles in said compartment for spraying water in the air passing therethrough, means including a pump in. said compartment for recirculating water from said sump through said nozzles, means forming outdoor air and recirculated inlets into said compartment, dampers in said inlets, means including a wet bulb thermostat exposed to outdoor air for adjusting the dampers in the recirculated air inlet towards closed position and the dampers in the outdoor air inlet towards open position, and for starting said pump when the wet bulb temperature of the outdoor air is below a predetermined maximum temperature and above a predetermined minimum temperature, an air heater in said compartment, and means including indoor thermostatic means for deenergizing said pump when the indoor temperature falls to a predetermined point and for. energizing said heater when the indoor temperature falls to a predetermined point below said first mentioned point.

4. Air conditioning apparatus comprising an air cooling compartment, air cooling tubes in said compartment, an ice water source, means for circulating water from said source through said tubes, spray nozzles in said compartment, said compartment having a sump in its lower portion, means including a pump in said compartment for recirculating water from said sump through said nozzles, means forming outdoor air and recirculated inlets into said compartment, dampers in said inlets, means including a wet bulb thermostat exposed tooutdoor air for adjusting the dampers in the recirculated air inlet towards closed position and the dampers in the outdoor air inlet towards open position, and for starting said pump when the wet bulb temperature of the outdoor air is below a predetermined maximum temperature and above a predetermined minimum temperature, and means including an indoor thermostat for actuating said first mentioned means to discontinue the supply of ice water to said tubes and for deenergizing said pump when the indoor temperature is below a predetermined point.

5. Air conditioning apparatus comprising an air cooling compartment, air cooling tubes in said compartment, an ice Water source, means for circulating Water from said source through said tubes, spray nozzles in said compartment, said compartment having a sump in its lower portion, means including a pump in said compartment for recirculating Water from said sump through said nozzles, means forming outdoor air and recirculated inlets into said compartment, dampers in 1 said inlets, means including a wet bulb thermostat exposed to outdoor air for adjusting the dampers in the recirculated air inlet towards closed position and the dampers in the outdoor air inlet towards open position, and for starting said pump when the wet bulb temperature of the 

